1. if或多重if判断 更适合于区间判断；
2. switch 分支判断 更适合于等值判断；
//byte,int,short,long,string
----------------------------------
class Demo2{
public static void main(String[] args){
int grade = 3;
switch(grade){
case 1:
System.out.println("*");
break;
case 2:
System.out.println("**");
break;
case 3:
System.out.println("***");
break;
default:
System.out.println("no grade");
break;
}
}
}
------------------------------
---------------switch 穿透作用
class Demo2{
public static void main(String[] args){
int year = 2019;
int month = 1;
int day = -1;
switch(month){
case 1:
case 3:
case 5:
case 7:
case 8:
case 10:
case 12:
day = 31;
break;
case 4:
case 6:
case 9:
case 11:
day = 30;
break;
case 2:
if(year % 4 == 0 || (year % 4 == 0 && year % 100 != 0)){
day = 29;
}else{
day =28;
}
default:
System.out.println("faults");
break;
}
if(day != -1){
System.out.println(year+""+month+""+day);
}
}
}
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